A frangible plug for use in a valve mechanism, and, more particularly, a single-use valve mechanism that may be used for discharging fluid is described herein. The frangible plug and valve mechanism may have particular use in the field of suppressant release, such as a fire suppressant fluid.
The examples described herein relate to devices and methods for the controlled release of a fluid flow substance. They are particularly suited, but not limited, to the controlled release of a suppressing or extinguishing agent from a cylinder. The devices and methods described may further be used for the rapid deployment of an extinguishing agent from a cylinder, such as those that may typically, although not exclusively, be used on moving platforms such as aircrafts, trains, military or commercial vehicles.
Such valves fall into two main groups; non-hermetic and hermetically sealed. The former category is typified by the high rate discharge (HRD) valves used on suppressors in military and commercial vehicles. These can be electromechanical or protractor fired, consisting of either a flapper or poppet as the main openings mechanism. Both systems contain multiple moving components and rely on O-ring seals for integrity. Such valves can be relatively expensive and require refurbishment prior to use.
Further applications, such as aerospace, require that the suppressor be hermetically sealed to minimise leakage over the required environmental range and to extend service life. Such hermetically sealed extinguishers use an explosive cartridge located on the outside of an outlet diaphragm, which upon actuation ruptures a disc and releases agent into a distribution network or directly into the protected fire zone. This method, although very fast and reliable, is prone to fragmentation of the diaphragm during actuation and requires the use of pyrotechnic cartridges. These valves require periodic maintenance and replacement and have associated handling, transit and storage restrictions.
The examples described herein aim to retain the rapid opening and free flow characteristics of the prior art, whilst reducing cost, removing pyrotechnic cartridges and providing the option for hermiticity where required.
DE 19736247 discloses a component having a body made of brittle material and the use of piezoelectric elements both embedded and laminated into the body such that, when the body is energized by the piezoelectric elements, a portion of the component is destroyed.
US 2010/025050 discloses a thermally activated sprinkler valve that includes a shape-memory element that expands as it is heated, forcing a bolt to break, thereby opening the sprinkler valve.
U.S. Pat. No. 6,682,521 describes numerous methods of opening a pressure containing vessel through the use of memory shape alloys.
European Patent Application No. 14160040 discloses a ceramic disc with a pre-defined stress plane which is fractured by impact by a point force. Means for braze attachment of the disc, means for minimising fragmentation and a means for retaining the free section of the disc after fracture are also disclosed.
EP 1582789 describes devices and methods for controlling the release of a substance which are particularly suited to the control of substances such as fire extinguishing media. The devices and methods described comprise a housing having an inlet for connection to a source of a substance and an outlet, with a passage extending therebetween. The passage may be closed by a frangible element which comprises a ceramic disc that is connected to a source of electrical current. The disc may be a metal oxide ceramic disc, and may be fractured by an electrical pulse which is applied to the disc.
GB 1378079 describes a bursting disc assembly, and in particular a vessel having an aperture sealed by the bursting disc assembly. The bursting disc assembly is comprised of toughened glass that is shattered by a movable spike which is projected against the glass with sufficient force to rupture the surface layer thereof and consequently shatter the disc. The spike is moved via pressure created by the ignition of a pyrotechnic composition.
GB 567120 discloses a quick-release valve arrangement for a container of fluid under pressure which is aimed at enabling fluid to be released in a simple and rapid manner. The valve arrangement comprises a hollow body or casing formed with a valve seat as well as a valve that is shaped to fit upon the valve seat to seal up the passage leading from the fluid container. A frangible disc, which may be formed from cast iron, pottery, glass or brittle plastic, is located within the valve body and spaced from the valve proper by a strut member which serves to hold the valve down on its seat. The device also includes a plunger that is used to shatter the disc and release the valve. The disc may also be shattered in other ways such as by providing an explosive charge or via a small projectile driven by the explosion striking the disc.
U.S. Pat. No. 7,703,471 discloses a remotely-operated single-action discharge valve for releasing gaseous, liquid, or dry material from a pressurized storage vessel. A frangible seal is provided within a valve body which seals the passage therethrough when the seal is intact. A solenoid is described which includes an armature moveable from a first position to a second position when the solenoid is actuated. The device includes a tooth, teeth or a pin or plurality of pins which break the frangible seal as the armature moves between the first and second position. The seals described are held in place using an o-ring and can be made of glass.